English
The range of the primed reindexed family equals the brange of f.
Русский
Диапазон перерандексированного семейства равен brange f.
LaTeX
$$$\mathrm{range}(\mathrm{familyOfBFamily'}\ r\ ho\ f) = \mathrm{brange}(o,f)$$$
Lean4
@[simp]
theorem range_familyOfBFamily' {ι : Type u} (r : ι → ι → Prop) [IsWellOrder ι r] {o} (ho : type r = o)
(f : ∀ a < o, α) : range (familyOfBFamily' r ho f) = brange o f :=
by
refine Set.ext fun a => ⟨?_, ?_⟩
· rintro ⟨b, rfl⟩
apply mem_brange_self
· rintro ⟨i, hi, rfl⟩
exact ⟨_, familyOfBFamily'_enum _ _ _ _ _⟩